Spark plug



Feb. 10, 1942. HALL 2,272,558

SPARK; PLUG Filed June 18, 1940 Patented Feb. 10, 1942 UNITED STATESPATENT QFFECE SPARK PLUG Earl M. Hall, Salem, reg., assignor of one-halfto Henry Carl, Salem, Oreg.

Application June 18, 1940, Serial No. 341,193

2 Claims.

This invention relates to improvements in spark plugs and the primaryobject of the invention is to design a plug that will not foul or becomeshort circuited.

Another object of the invention is the provision within the plug for aircooling the same by air circulation.

These and other incidental objects will be apparent in the drawing,specification and claims to follow.

Referring to the drawing:

Figure l is a side elevation of my new and im proved spark plug.

Figure 2 is a sectional View of the plug, parts broken away forconvenience of illustration.

Figure 3 is a plan sectional view, taken on line 33 of Figure 2.

Figure 4 is another preferred form of embodiment of my new and improvedspark plug.

Figure 5 is a plan view of Figure 4.

In the drawing:

I is the main body portion of the spark plug, having the usual threadedextensions 2 for entering the motor block. The usual central electrode 3is encased within the porcelain or insulating material 4 of usualconstruction. The lower end 2 of the plug is cored out at 5, slightlylarger than the lower end 6 of the insulator 4. The lower end of thecore 5 is partially closed by the bottom I of the lower part of the plug2. A cup-like insulator gasket 8 rests on the bottom I and receives thelower portion of the insulator 6, best shown in Figure 2. The end I hasan opening 9 larger than the lower end III of the electrode 3. This iswhere the spark gap is provided.

It will be noted that the opening 9 is very shallow, leaving no placefor dirt to lodge. The power of the explosion will clean this spark gapchamber from any foreign matter. It will be noted that the end 1 of thelower part 2 of the spark plug is rounded in the shape of a semicircle.The reason for this construction is to provide self-cleaning of the endof the plug by the power of explosion within the cylinder head. This isa very important feature of my new and improved spark plug.

In the construction of the lower part of the porcelain 6, the gasket 8seals all of the space between the porcelain and the lower body of theplug 2 so that there is no space for dirt or carbon to generate. This isanother high-light of the invention, which is very important. The onlyspace provided is the space 9 where the spark takes place and this spaceis so shallow that no dirt can lodge without being forced out bycombustion.

Another feature is the provision of ventilators I I within the body ofthe plug I for allowing air to reach the insulator 4, spaced around itslower end 6 for cooling the same. There are a number of ventilatoropenings II provided for this purpose, terminating in the hollow chamberI2 which is connected to the space 5 surrounding the lower terminal 6 ofthe insulator 4. The insulator 4 is held in place by the usual lock nutI3 and gasket I l.

The cup-like gasket 8 may be made of insulating material in which casethe bottom part of the gasket could extend over to th electrode III orthe gaskets may be made of metallic material and extend to the edge ofthe openings 9, as shown in Figure 2. This material should expand tocorrespond with the rest of the plug so that a tight fit may bemaintained.

Referring to Figures 4 and 5, I illustrate another preferred form ofinsulator terminal mounting, where the lower end I6 of the insulatingterminal is made relative short resting within the insulating materialIT. The shoulder I8 of the insulator is forced downward by the gasket I9underneath the locking nut 20, which is threaded into the main body ofthe spark plug I5. In this construction the distance between the lockinggasket I9 and the lower end of the insulator terminal I6 is shortened;this is desirable when it comes to expansion by heat. The lower end ofthe locking nut 20 ha openings or notches 2IA leadin to the verticalgrooves 2I. This permits the circulation of air from openings 22 withinthe main body of the plug I5 where air is allowed to pass from theatmosphere through the openings 22 and openings 2IA and up through thegroove or flute 2I around the main insulator terminal, cooling the wholeassembly.

I do not wish to be limited to the particular mechanical constructionillustrated and claimed, as other forms of mechanical embodiment may beemployed, still coming within the scope of the claims to follow.

What is claimed as new is:

1. A spark plug including a metallic body formed with a threadedextension to secure the plug in place, the lower end of the extensionbeing formed with an annular opening forming an electrode, the lower endof the body being upwardly curved from the edge of the opening, aninsulating body having a part seated within the extension and spacedfrom an interior bore thereof, the body being circumferentially enlargedabove the parts fitted within the extension, a strip arranged betweenthe extension of the insulating body and the wall of the bore the loweredge of the strip terminating in line with the edge of the opening andthe upper edge of the strip terminating within the extension below theenlargement of the insulating body, said strip underlying and forming asupport for the insulating body, an electrode extending longitudinal- 1yof the insulating body and terminating within and spaced from the wallof the opening in the lower end of the threaded extension of the me- 10sulating within the bore of the threaded extension is of insulatingmaterial.

EARL M. HALL.

